Jealousy...normal I guess

As the days, weeks, and months go by, it is definitely getting easier to accept what God has dealt us with Brycen. But I still have many days where I feel so much jealousy...at the store when I hear a toddler saying clear words, when friends/family comment on Facebook about their child learning their ABC's or counting, when seeing/hearing a 3 yr old is successful in potty training, when a 3 yr old is put in time-out and actually sits there, when two siblings are playing together outside or at the playground...and the list goes on. I feel jealous when I see these things, but then again I know that as parents to Brycen, we will never take a simple word he says or accomplishment he learns for granted!
I feel bad when I feel this way, but I just can't help it! I compare Brycen to other children, mostly to determine what we seriously need to work on that is typical for his age, but I also find myself once again wondering "why?" I think I will never stop wondering that...I think it is human nature to always question the things that happen to us, whether good or bad.
When I was pregnant with Aubree, Mike and I had already discussed not having any more children. Then when Brycen was initially diagnosed, we confirmed with ourselves that we didn't think it was fair to either of them if we had another child as Brycen needs so much of our attention and energy. But then I also wonder if that is fair to Aubree...she will not know what it is like to have a sibling to play with or to share secrets with and so on. When Mike and I are gone someday, it will be up to Aubree to take care of Brycen (unless of course we experience some wonderful research miracles that help him to become more independent and find successful treatments for him!). I see the joy in her little face and hear the constant giggles for those few moments each day when he pays attention to her! She doesn't usually mind when he knocks her over or purposely runs into her, because she is craving any kind of attention he will give her. Then, within seconds, I watch as she is following him around, trying to capture his attention and wanting him to play like a typical sibling would. It makes me sad that she may never have that close sibling relationship...but then again, maybe they will have a different type of close relationship where she will become more of a mother to him and will teach him things as they are growing up.
So, I guess though I may be jealous of some things...I know that there is positive that goes along with the negative. How the day starts or what happens during the day will determine whether I view the glass as half full or half empty that day...and that view can change many times throughout the day!